Projection system with improved deformable medium



F. F. HOLUB Aug. 30, 1966 PROJECTION SYSTEM WITH IMPROVED DEFORMABLE MEDIUM Filed Jan. :24, 1964 35 Screen Fig. 2.

lnvemor: Fred F Ho/ub,

by QJQM Fig.

Electron Gu His Afforney.

United States Patent 3,270,133 I PROJECTION SYSTEM WITH IMPROVED DEFORMABLE MEDIUM Fred F. Holub, Scotia, N.Y., assignor to General Electric Company, a corporation of New York Filed Jan. 24, 1964, Ser. No. 339,930 11 Claims. (Cl. 1787.87)

This invention is concerned with a projection system comprising a container having a conducting interior, a deformable medium in said container that decreases in resistivity with decreases in thickness and in the presence of an electrical charge on the surface thereof, electron beam means, and a light and optical system for projecting light as a function of the deformations of said medium, said deformable medium comprising a composition selected from the class consisting of compounds (a) of the formula ESiOSiE 0 and (b) of the formula Where m is a whole number equal to from 0 to 1.

'In US. Patent 2,943,147, issued June 28, 1960, (and similarly in US. 2,391,450 issued December 25, 1945), assigned to the same assignee as the present invention, there is disclosed and claimed a projection system employing a deformable medium having .a high resistivity which is velocity modulated. In general, this apparatus which is illustrated in FIGURE 1 of the attached drawing, comprises an evacuated glass envelope containing an electron gun 11 for producing an electron beam 13 and deflecting it in a rectangular raster over the surface of a transparent, deformable medium 15 that is within a portion 17 of the transparent container; an enlarged view of this portion of the assembly is shown in FIG- URE 2. The beam 13 is preferably velocity modulated by a television signal that is applied to the deflection means (not shown) in the electron gun 11. The deformable medium 15 has a center portion 19 of decreased thickness, coincident with the raster area of the beam 13, which is produced by electrons from the beam 13 that are attracted .to a conducting coating 21 on the inner surface of the container 17. These electrons also produce deformations in the surface of the deformable medium 15, the amplitudes of which are a function of the number of electrons deposited by the beam 13 at the various points on the surface of the medium 15. Consequently, the amplitudes of these deformations are a function of the television signal modulating electron beam 13.

These deformations are utilized to diffract light from a light source 23 in an optical system which is illustrated as including a lens 24 that images light source 23 on the surface of medium 15 through a bar and slit system 25. Another lens 29 images the slits of system on the bars of another bar and a slit system 31 in .the absence of deformations in the surface of the deformable medium. However, any deformations phase diffract the light so that it passes through the slits in the system 31 with an intensity that corresponds to the amplitudes of the deformations and thus the amplitudes of the applied television signal.

The light passing through system 29 is imaged by a projection lens 33 on a screen 35 after reflection from a mirror 37.

If a conventional deformable medium is utilized in the illustrated system, the average charge density pro duces a force on the medium 15 that overcomes the surface tension from the excess medium outside the raster area and decreases the portion 19 of medium 15 to zero thickness; under such conditions no deformations can be formed and the system becomes inoperative until the medium is replaced.

In this US. Patent 2,943,147, it is stated that if the medium has the property of decreasing in resistivity with decreasing thickness, portion 19 does not decrease to zero thickness under the pressure of the charges but rather maintains a thickness the value of which is a function of the magnitude of charge density on the surface of the medium 15. With a decrease in resistivity, the time constant is decreased for the passage of leakage current from the surface of the deformable medium to the conducting coating 21 beneath it, resulting in increase in leakage current, which decreases the charge density on the surface of the medium, thereby relieving the pressure somewhat. Ultimately, an equilibrium condition is attained in which the pressure from the charges on the surface of the medium equals the pressure from the surface tension on the excess medium around the raster. Then the thickness at this equilibrium condition is maintained. The charge density on the surface of the medium never decreases to zero due to the leakage because it is continually being replaced by the electrons from the beam 13.

The deforma'ble compositions described in US. Patent 2,943,147 as suitable for the medium are required to be transparent, be capable of withstanding electron bombbardment without significant decomposition, or change in viscosity over long periods of time, have a viscosity at the operating temperature (between about 25 C. and C.) of approximately 50 to 50,000 centistokes, and the deformable composition must not decompose the conducting coating. The medium must also have a resistivity that varies within the range of approximately 10 to 10 ohms-cm, with the average resistivity at the stable thickness being approximately 10 ohms-cm.

Among the deformable media or fluids described in this patent are, for instance, beeswax, methyl silicone fluids, methyl silicone fluids containing up to 5% of phenyl silicones, methylphenyl silicones containing an average of two methyl and phenyl groups per silicon atom in which the rnol ratio of methyl groups to silicon atoms is greater than 0 and less than 2, etc. However, it has been found that these deformable fluids are not as stable as one would desire because under the influence of an electron beam, the deformable medium or deformable fluid tends to increase undesirably in viscosity, and with continued use of the projection system described above, the viscosity increases to a point where gel particles begin to form and ultimately the deformable medium gels; of

course, this means that the apparatus can no longer be used with that particular deformable medium.

Unexpectedly, I have discovered that a group of organic compositions of Formulas I .and H described previously, is eminently suitable as the deformable mediumirradiation and therefore are more stable in the presence of the electron beam used in the aforesaid projection system. The compositions employed by me in the aforesaid projection system can be used continuously for much longer periods of time without significant physical change in the deformable medium, thus adding greatly to the life of the projection system.

Within the scope of Formulas I and II described above, many compositions can be employed for the purpose and the following examples are given by way of illustration and not by way of limitation as to the preparation of a large number of these compositions which can be employed as the deformable medium in the aforesaid projection system. It is to be under-stood that Where the biphenylyl (xenyl) or phenoxyphenyl radical is present in the composition used as the deformable medium, the phenyl radicals of the bi-phenylyl group and the phenoxy radical of the phenoxyphenyl group may be ortlio-, metaor parato the point of attachment in the bi-phenylyl or in the phenoxyphenyl radical shown in Formulas I and H. Thus the biphenylyl radical may be illustrated and the phenoxyphenyl radical may be illustrated as I The naphthyl radical can be attached to the oxygen in the a or B positions.

In general, the above-mentioned disiloxanes may be formed by eifecting reaction between a hexahalogenodisiloxane, for example, hexachlorodisiloxane having the formula Cl SiO-Si-C1 with either a phenylphenol or a phenoxyphenol of the formula III OH l or a naphthol of the formula IV where m has the meaning given above and the hydroxyl group of the naphthol is in the a or [3 position. Ordinarily, it is only necessary to employ 1 mol of the hexaohlorodisiloxane with 6 or more mols of the hydroxyphenyl or hydroxynaphthol compound, mix the reactants together preferably in the presence of a hydrohalide acceptor such as pyridine, tertiary alkyl amines, etc., and thereafter heat the mixture of ingredients at temperatures up to ZOO-325 C. until such time as the desired aryloxy-substit'uted disiloxane of Formulas I and II is obtained. Usual purifications such as distillations and crystallizations can be employed to obtain pure products. If desired, the hexachlorodisiloxane can be reacted with mixtures of the phenylphenols or the phenoxyphenols, where the phenol group or the phenoxy group on the phenyl phenol or phenoxyphenol, respectively, is attached in diflferent positions such as ortho-, metaor parato the hydroxyl group. In the same fashion one can make mixed hexanaphthyloxy disiloxanes by em- VII ploying mixtures of a-na-phthol and B-naphthol, or one can make mixed naphthyloxy disiloxanes containing phenylphenoxy or phenoxy henoxy groups in addition on the silicon atoms of the disiloxane.

Ordinarily, it may not be necessary to separate mixtures of di-siloxanes of the Formulas I and II. Thus, for example, hexachlorodisiloxane can be reacted with a mixture of o-phenylphenol and p-phenylphenol in the desired molar proportions, and the reaction mixture can be treated to remove unreacted ingredients and undesirable by-products, retaining a mixture of disiloxanes in which the silicon atoms are substituted with ortho-phenylphenoxy groups and para-phenylphenoxy groups.

In order that those skilled in the art may better understand how the present invention may be practiced, the following examples are given by way of illustration and not by way of limitation. Unless otherwise stated, all parts are by weight.

EXAMPLE 1 A reaction vessel was flushed with nitrogen and thereafter charged with 61 grams of hexachlorodisiloxane, 282 grams o-phenylphenol and 1 gram of pyridine (as hydrohalide acceptor). The mixture was slowly heated over a 20-minute period at a rising temperature of from 50- 270 C. Heating Was then continued for 30 minutes at a temperature of 270310 C. until essentially all HCl evolution had stopped. On cooling to C. a viscous liquid was obtained, which was subjected to vacuum distillation to remove unreacted ortho-phenylphenol and hexachlorodisiloxane. Further, fractional distillation yielded a product boiling at about 340-352 C. at about 45 microns. Analysis of the compound showed it to contain 80.42 percent carbon, 5.12 percent hydrogen, and 4.6 percent silicon as contrasted to the theoretical values of 79.52 percent carbon, 5.00 percent hydrogen, and 5.16 percent silicon. This composition had the formula EXAMPLE 2 In this example, 28 grams (0.10 mol) hexachlorodisiloxane and 104 grams (0.61 mol) p-phenylphenol were reacted in the same manner as described in Example 1, employing a heating schedule of 20 minutes at a temperature of 50-150 C. and 30 minutes at a temperature of 200300 C. The reaction product was then worked up in the same fashion as that employed in Example 1 to give a material boiling at around 380 C. at about 12 microns. Analysis of this composition showed it to be the compound having the formula EXAMPLE 3 In this example, 13.45 grams (0.05 mol) hexachlorodisiloxane and 59.58 grams (0.32 mol) p-hydroxyphenyl ether were reacted similarly as was done in Example 1 with the exception that the heating schedule was for 20 minutes at 50-170 C. and for 30 minutes at 270 C. The reaction product was then worked up in the same manner as was done in Example 1 to yield a product boiling around 345-360 C. at 12 microns which upon analysis was identified as the composition having the formula 5 EXAMPLE 4 In this example, 13.5 grams (0.05 mol) hexachlorodisiloxane was mixed with 27.23 grams (0.16 mol) phenylphenol and 27.23 grams (0.16 mol) p-phenylphenol. The mixture of ingredients was heated similarly as was done in Example 1 with the exception that the heating schedule was for 20 minutes at 50170 C. and 30 minutes at 200-300" C. The reaction mixture was thereafter worked up in the same fashion as in Example 1 to obtain a product boiling at about 375-390 C. at 12 microns. Analysis of the material showed it to comprise a mixture of disiloxanes of Formulas V and VI, but con sisted predominantly of disiloxanes in which p-phenylphenoxy and o-phenylphenoxy radicals, totaling six in number, were randomly distributed around the two silicon atoms of the disiloxane. The molar proportions of the o-phenylphenol and p-phenylphenol initially used to make the disiloxanes are reflected in the molar proportions of the o-phenylphenoxy and p-phenylphenoxy radicals derived therefrom. Thus, the molar concentrations of such o-phenylphenol and p-phenylphenol may be varied from 5 to 95 mole percent of the former to 95 to 5 mole percent of the latter. Among such randomly distributed phenylphenoxy disiloxanes which are obtained in this manner are those of the general formula where the substituent phenyl groups may be ortho, meta, or para, to the phenoxy radical on which it is substituted. Among such disiloxanes which may be present based on the use of o-phenylphenol and p-phenylphenol are, for instance, 1,1,3,3-tetra (p-phenylphenoxy)-1,3-di (o-phenylphenoxy) disiloxane; 1,1,3,3-tetra (o-phenylphenoxy)-l,3- di (p-phenylphenoxy) disiloxane, 1,3,3-tri(p-phenylphenoxy)-1,1,3-tri(o-phenylphenoxy) disiloxane, etc.

EXAMPLE 5 Hexanaphthyloxy disiloxane of the formula is prepared by effecting reaction between hexachlorodisiloxane and either alpha-naphthol or beta-naphthol, or mixtures of such naphthols, employing a molar ratio of about 1 mol of the former to 6 mols of the naphthol. The mixture of ingredients is heated similarly as in Example 1 at temperatures ranging up to 300350 C. for times of the order of 20-40 minutes and thereafter the hexanaphthyloxy disiloxane (or mixtures of such disiloxanes) is isolated.

In order to determine (b3 means of an accelerated test) the radiation resistance of the aforesaid compositions in an electron beam, which would be the conditions under which these fluids would be expected to operate in the above-described projection system, the fluid of Example 1 was subjected to electron irradiation with a 1500 kv. resonant transformer at a current input of 200-500 microamperes at a dose rate of 20-50 10 roentgens/minute, to a total dose of 800 megaroentgens. The following Table I shows the total number of molecules of gas per electron Volts absorbed (identified as G gas) and the percentage of each of the gases liberated by virtue of the irradiation. Table II shows the viscosity at various temperature before and after irradiation of the samples.

The exceptionally low gas value and the small change of viscosity under the highly accelerated test conditions applied to the above-identified compositions as shown in Tables I and 11 above established the eminent suitability of this composition as the deformable medium in place of the deformable media disclosed in the aforesaid Patent 2,943,147. When this composition was placed in the projection system described in the attached drawing, clear images were obtained and the fluid could 'be used over long periods of time without any apparent evidence of either degradation or gelation of the deformable medium.

EXAMPLE 6 When the compositions of Examples 2 to 5 are substituted in place of the composition of Example 1 and are tested for gas values and viscosity change under the accelerated test conditions described above, the same low gas Values and small differentials in viscosity changes are obtained. When these same compositions are employed as the deformable media in the projection system described in the accompanying drawing, clear images again are obtained.

It will of course be apparent to those skilled in the art that in addition to the disiloxane compositions described above as being useful for the claimed projection system, other disiloxanes coming within the scope of Formulas I and II can be employed without departing from the scope of the invention. Among such compositions which additionally may be employed are, for instance, orthoand meta-substituted phenoxyphenyl disiloxanes where the phenoxy radical is orthoor metato the phenylene radical attached through the medium of an oxygen atom to the silicon atom; hexa-(alpha-naphthyloxy) disiloxane; hexa-(beta-naphthyloxy) disiloxane, etc.

In addition to employing the above compositions either separately or in combination thereof as the deformable medium in the projection system herein described, they can be mixed with other organopolysiloxanes such as those disclosed in Rochow patents U.S. 2,258,221 and 2,258,222 and in this manner used as the deformable medium. However, under such conditions, it is advantageous that the amount of organopolysiloxane combined with the above described disiloxanes is in a minor proportion and preferably below 25 percent, by weight, based on the total weight of the organopolysiloxane and the disiloxane,

7 What I claim as new and desire to secure by Letters Patent of the United States is:

1. A projection system comprising a container having a conducting interior, a deformable medium in said container comprising a composition selected from the class consisting of compounds of the formula and of the formula and mixtures of the aforesaid compositions, where m is a whole number of from to 1, an electron beam means for producing an electrical charge on the surface of said deformable medium as a function of an applied electrical signal and cooperating with said conducting interior to subject the medium to a deforming force to produce deformations on the surface of said medium, and a light and optical system for projecting light as a function of the deformations on the surface of said medium.

2. A projection system as in claim 1 in which the deformable medium is a phenoxy disiloxane of the formula 3. A projection system as in claim 1 in which the deformable medium is a phenoxy disiloxane of the formula Ora-Q) 6. A projection system as in claim 1 in which the deformable medium is a hexanaphthyloxy disiloxane of 7. A composition of matter for the projection system of claim 1 selected from the class consisting of compounds of the formula and @a in mixtures of said compositions, where m is a whole number equal to from O to l.

8. A composition of matter for the projection system of claim 1 having the formula 4. A projection system as in claim 1 in which the deformable medium is a phenoxy disiloxane of the formula 9. A composition of matter for the projection system of claim 1 having the formula @Q- -k k -Q-Ql 5. A projection system as in claim 1 in which the deformable medium is a mixture of phenylphenoxy disiloxanes of the formulas 10. A composition of matter for the projection system of claim 1 having the formula 9 10 when the phenyl radical is one of the following positions 3,027,394 3/ 1962 Pierce et a1. 260448.8 relative to the phenoxy radical: ortho, meta, para. 3,033,783 5/1962 Trautman 252 49'6 References Cited by the Examiner 3,192,241 6/ 1965 R k 260443.8

UNITED STATES PATENTS 5 2,943,147 6/1960 Glenn 178 75 DAVID G. REDINBAUGH, P1 lmary Exammel.

3,016,417 1/1962 Mast et a1 178-75 R. RICHARDSON, Assistant Examiner. 

1. A PROJECTION SYSTEM COMPRISING A CONTAINER HAVIING A CONDUCTING INTERIOR, A DEFORMABLE MEDIUM IN SAID CONTAINER COMPRISING A COMPOSITION SELECTED FROM THE CLASS CONSISTING OF COMPOUNDS OF THE FORMULA 